Setting Fires In Space

The Burning and Suppression of Solids (BASS) experiment aboard the ISS seeks to teach scientists about fire in space. Microgravity environments cause things, like fire, to behave differently. Add in the oxygen enriched atmospheres of spacecraft and fire can be a real problem. If we are going to send humans on multi-year journeys to Mars and asteroids, then being able to predict these fires and have systems that can suppress and extinguish them are important. So, for the sake of future astronauts, today’s astronauts are setting little fires on the ISS so scientists can study them and so the rest of us can look at the pretty pictures.

Neat! I don't often think outside the atmosphere, but now I'm kind of curious which direction heat goes in a sealed, pressurized container. It rises through the atmosphere, but that's because the pressure is lower upstairs. Do you get a literal 'ball of fire' in a capsule?

Also wouldn't the expanding gasses raise the pressure inside the capsule?